(abstract) Venus Gravity Data Reduction

Abstract:

The Magellan spacecraft has provided high resolution gravity data to its very end, October 13, 1994, when it was consumed by the Venusian atmosphere. After aerobraking in August of 1993 to attain a near circular orbit, excellent high latitude data were acquired which previously were very weak during the elliptical orbit coverage. There are 1500 orbits during the near circular orbit, supplying redundant coverage at different geometries over many features. This allowed the relaxation of apriori constraints, so true amplitudes are being extracted from the data. In this paper we present the results of a 75<SUP>th</SUP> degree and order field that incorporates all the old Pioneer Venus Orbiter data as well as all the Magellan data to September 1994. The new results reflect even higher correlation with topography, higher amplitude values for the highs and lows, and global results that have essentially very little apriori constraint on the solution parameters. We also correlate our new model with the earlier ones based on 60<SUP>th</SUP> and 40<SUP>th</SUP> degree and order presentations.